<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app"></div>

    <template id="why">
        <div>
            <h2>{{counter}}</h2>    
            <button @click='increment'>+1</button>
            <button @click='decrement'>-1</button>
        </div>  
    </template>

    <script src="../vue/vue.js"></script>
    <script>

        Vue.createApp({
            template: `#why`,
            data() {
                return {
                    counter: 100
                }
            },
            methods: {
                increment() {
                    this.counter++
                },
                decrement() {
                    this.counter--
                }
            }
        }).mount('#app');

            
    </script>
</body>
</html>